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| Format: | Artículo científico |
| Language: | es |
| Published: |
Universitat de Barcelona
2016
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| Online Access: | https://www.redalyc.org/articulo.oa?id=50547614007 https://www.redalyc.org/journal/505/50547614007/ https://www.redalyc.org/journal/505/50547614007/html/ https://www.redalyc.org/journal/505/50547614007/50547614007.epub https://www.redalyc.org/journal/505/50547614007/movil |
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Table of Contents:
- Orthophragminids with new axial thickening structures from the Bartonian of the Indian subcontinent E. Ozcan P. Kumar Saraswati M. Hanif N. Ali Ciencias de la Tierra Bulges Foraminiferida Omphaloid tests Orthophragminids Indian subcontinent The ‘axial thickening’, a morphological character of certain Eocene orthophragminids refers to the thickening of the equatorial and/or lateral layers in axial directions forming radial external structures, namely the ribs. The occurrence of ribs is considered to be a diagnostic speci c character of the orthophragminids in the peri-Mediterranean region and Europe (western Tethys). In the Bartonian orthophragminids of the Indian subcontinent we observe a new type of axial thickening that we name ‘bulges’. The bulges are semi-rounded to rounded, localized structures on the test surface formed solely by the greater development of lateral chamberlets. These specimens, with trybliolepidine to umbilicolepidine type embryon con guration, co-occur with ribbed discocyclinids having completely different internal features. We also record another type of axial thickening of the lateral layers in notably small omphaloid tests that are characterized by a thick umbo, deeply depressed at the center such that the periphery of it forms a thick circular structure. The reported omphaloid specimens possess a small, semi- isolepidine to nephrolepidine type embryon con guration and characteristic early chambers, not comparable to any known species in the Tethys. These specimens occasionally may have incomplete and/or irregular septula, reminiscent of certain Caribbean orthophragminids. The specimens with bulges, identi ed in two geographically distant regions of the Indian subcontinent, possibly represent endemic foraminiferal fauna con ned to the Indo- Pakistan region. We introduce two new species, Discocyclina kutchensis sp. nov. (characterized by bulges) and ‘D’. sulaimanensis sp. nov. (characterized by circular structures in omphaloid tests). The status of both taxa in the Tethys is discussed. 2016 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50547614007 https://www.redalyc.org/journal/505/50547614007/ https://www.redalyc.org/journal/505/50547614007/html/ https://www.redalyc.org/journal/505/50547614007/50547614007.epub https://www.redalyc.org/journal/505/50547614007/movil es http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.3 Vol.14